High performance electrodes modified by TiCN for vanadium redox flow batteries

Abstract

Graphite felts (GFs) are the main materials for electrodes in vanadium redox flow batteries (VRFBs) due to their high stability, excellent conductivity and large surface area. However, the poor electrochemical activity of GFs constrains the performance of VRFBs. In this study, the titanium carbonitride (TiCN) nanoparticles are employed to modify the graphite felt electrodes of VRFBs to enhance the sluggish electrochemical kinetics of the V²⁺/V³⁺ redox reactions. Cyclic voltammetry (CV) results demonstrate that the oxidation peak shifts negatively by 0.0917 V when the electrode is modified with TiCN nanoparticles compared to carbon nanoparticle-modified GFs, indicating improved electrochemical kinetics. Furthermore, the full battery charge-discharge test reveals that the energy efficiency of the TiCN-modified GFs reaches 86.6 % at a current density of 100 mA cm⁻², surpassing the efficiencies of the carbon-modified GFs (81.4 %) and the pristine GFs (76.7 %). These results suggest that TiCN nanoparticles significantly enhance the electrochemical kinetics of the V²⁺/V³⁺ redox reactions on GFs.